What Is Gout?
Gout is one of the most painful rheumatic diseases. It
results from deposits of needle-like crystals of uric acid in connective
tissue, in the joint space between two bones, or in both.
These deposits
lead to inflammatory arthritis, which causes swelling, redness, heat,
pain, and stiffness in the joints. The term arthritis refers to
more than 100 different rheumatic diseases that affect the joints,
muscles, and bones, as well as other tissues and structures. Gout
accounts for approximately 5 percent of all cases of arthritis.
Pseudogout is sometimes confused with gout because it
produces similar symptoms of inflammation. However, in this condition,
also called chondrocalcinosis, deposits are made up of calcium phosphate
crystals, not uric acid. Therefore, pseudogout is treated somewhat
differently and is not reviewed in this booklet.
Uric acid is a substance that results from the breakdown
of purines, which are part of all human tissue and are found in many
foods. Normally, uric acid is dissolved in the blood and passed through
the kidneys into the urine, where it is eliminated. If the body
increases its production of uric acid or if the kidneys do not eliminate
enough uric acid from the body, levels of it build up in the blood (a
condition called hyperuricemia). Hyperuricemia also may result when a
person eats too many high-purine foods, such as liver, dried beans and
peas, anchovies, and gravies. Hyperuricemia is not a disease and by
itself is not dangerous. However, if excess uric acid crystals form as a
result of hyperuricemia, gout can develop. The excess crystals build up
in the joint spaces, causing inflammation. Deposits of uric acid, called
tophi (singular: tophus), can appear as lumps under the skin around the
joints and at the rim of the ear. In addition, uric acid crystals can
collect in the kidneys and cause kidney stones.
For many people, gout initially affects the joints in the
big toe. Sometime during the course of the disease, gout will affect the
big toe in about 75 percent of patients. It also can affect the instep,
ankles, heels, knees, wrists, fingers, and elbows. The disease can
progress through four stages:
- Asymptomatic (without symptoms) hyperuricemia--In this
stage, a person has elevated levels of uric acid in the blood but no
other symptoms of gout. A person in this stage does not usually require
treatments for gout.
- Acute gout, or acute gouty arthritis--In this stage,
hyperuricemia has caused the deposit of uric acid crystals in joint
spaces. This leads to a sudden onset of intense pain and swelling in
the joints, which also may be warm and very tender. An acute attack
commonly occurs at night and can be triggered by stressful events,
alcohol or drugs, or the presence of another illness. Early attacks
usually subside within 3 to 10 days, even without specific gout treatments,
and the next attack may not occur for months or even years. Over time,
however, attacks can last longer and occur more frequently.
- Interval or intercritical gout--This is the period between
acute attacks. In this stage, a person does not have any gout symptoms and
has normal joint function.
- Chronic tophaceous gout--This is the most disabling stage
of gout and usually develops over a long period, such as 10 years. In
this stage, the disease has caused permanent damage to the affected
joints and sometimes to the kidneys. With proper gout treatments, most
people with gout do not progress to this advanced stage.
What Causes Gout?
A number of risk factors are related to the development of
hyperuricemia and gout:
- Genetics may play a role in determining a person's risk, since up
to 18 percent of people with gout have a family history of the
disease.
- Gender and age are related to the risk of developing gout; it is
more common in women and adults than in children.
- Being overweight increases the risk of developing hyperuricemia
and gout because there is more tissue available for turnover or
breakdown, which leads to excess uric acid production.
- Drinking too much alcohol can lead to hyperuricemia because it
interferes with the removal of uric acid from the body.
- Eating too many foods rich in purines can cause or aggravate gout
in some people.
- An enzyme defect that interferes with the way the body breaks down
purines causes gout in a small number of people, many of whom have a
family history of gout.
- Exposure to lead in the environment can cause gout.
Some people who take certain medicines or have certain
conditions are at risk for having high levels of uric acid in their body
fluids. For example, the following types of medicines can lead to
hyperuricemia because they reduce the body's ability to remove uric
acid:
- Diuretics, which are taken to eliminate excess fluid from the body
in conditions like hypertension, edema, and heart disease, and which
decrease the amount of uric acid passed in the urine;
- Salicylates, or anti-inflammatory medicines made from salicylic
acid, such as aspirin;
- The vitamin niacin, also called nicotinic acid;
- Cyclosporine, a medicine used to suppress the body's immune system
(the system that protects the body from infection and disease) and
control the body's rejection of transplanted organs; and
- Levodopa, a medicine used to support communication along nerve
pathways in the treatment of Parkinson's disease.
Who Is Likely To Develop Gout?
Gout occurs in approximately 840 out of every 100,000
people. It is rare in children and young adults. Adult men, particularly
those between the ages of 40 and 50, are more likely to develop gout
than women, who rarely develop the disorder before menopause. People who
have had an organ transplant are more susceptible to gout.
Gout Symptom & Diagnosis
Gout may be difficult for doctors to diagnose because the
symptoms may be vague, and they often mimic other conditions. Although
most people with gout have hyperuricemia at some time during the course
of their disease, it may not be present during an acute attack. In
addition, having hyperuricemia alone does not mean that a person will
get gout. In fact, most people with hyperuricemia do not develop the
disease.
To confirm a diagnosis of gout, a doctor may insert a
needle into an inflamed joint and draw a sample of synovial fluid, the
substance that lubricates a joint. A laboratory technician places some
of the fluid on a slide and looks for monosodium urate crystals under a
microscope. Their absence, however, does not completely rule out the
diagnosis. The doctor also may find it helpful to examine chalky, sodium
urate deposits (tophi) around joints to diagnose gout. Gout attacks may
mimic joint infections, and a doctor who suspects a joint infection
(rather than gout) may check for the presence of bacteria.
Signs and Symptoms of Gout
- Hyperuricemia
- Presence of uric acid crystals in joint fluid
- More than one attack of acute arthritis
- Arthritis that develops in 1 day, producing a swollen, red,
and warm joint
- Attack of arthritis in only one joint, usually the toe,
ankle, or knee
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Gout Treatments
With proper treatment, most people are able to
control their gout symptom and live productive lives. Gout can be treated
with one or a combination of therapies. The goals of gout treatment are to
ease the pain associated with acute attacks, to prevent future attacks,
and to avoid the formation of tophi and kidney stones. Successful
gout treatments can reduce both the discomfort caused by gout symptom
and long-term damage of the affected joints. Treatment will help to
prevent disability due to gout.
The most common gout treatments for an acute attack are
high doses of nonsteroidal anti-inflammatory drugs (NSAIDs) taken orally
(by mouth) or corticosteroids, which are taken orally or injected into
the affected joint. NSAIDs reduce the inflammation caused by deposits of
uric acid crystals but have no effect on the amount of uric acid in the
body. The NSAIDs most commonly prescribed for gout are indomethacin
(Indocin*) and naproxen (Anaprox, Naprosyn), which are taken orally
every day. Corticosteroids are strong anti-inflammatory hormones. The
most commonly prescribed corticosteroid is prednisone. Patients often
begin to improve within a few hours of treatment with a corticosteroid,
and the attack usually goes away completely within a week or so.
* Brand names included in this booklet are
provided as examples only, and their inclusion does not mean that these
products are endorsed by the National Institutes of Health or any other
Government agency. Also, if a particular brand name is not mentioned,
this does not mean or imply that the product is
unsatisfactory.
When NSAIDs or corticosteroids do not control a gout symptom,
the doctor may consider using colchicine. This drug is most effective
when taken within the first 12 hours of an acute attack. Doctors may ask
patients to take oral colchicine as often as every hour until joint
symptoms begin to improve or side effects such as nausea, vomiting,
abdominal cramps, or diarrhea make it uncomfortable to continue the
drug.
For some patients, the doctor may prescribe either NSAIDs
or oral colchicine in small daily doses to prevent future attacks. The
doctor also may consider prescribing medicine such as allopurinol
(Zyloprim) or probenecid (Benemid) to treat hyperuricemia and reduce the
frequency of sudden attacks and the development of tophi.
Stay Healthy: Medications, Gout Diet & Exercise
- To help prevent future attacks, take the medicines your doctor
prescribes. Carefully follow instructions about how much medicine to
take and when to take it. Acute gout is best treated when symptoms
first occur.
- Tell your doctor about all the medicines and vitamins you take. He
or she can tell you if any of them increase your risk of
hyperuricemia.
- Plan followup visits with your doctor to evaluate your progress.
- Gout Diet: Maintain a healthy, balanced diet; avoid foods that are high in
purines; and drink plenty of fluids, especially water. Fluids help
remove uric acid from the body.
- Exercise regularly and maintain a healthy body weight. Lose weight
if you are overweight, but do not go on diets designed for quick or
extreme loss of weight because they increase uric acid levels in the
blood.
What Research Is Being Conducted To Help People With
Gout Symptom?
Scientists are studying which NSAIDs are the most
effective gout treatments, and they are analyzing new compounds to
develop safe, effective medicines to lower the level of uric acid in the
blood and to treat gout symptom. They also are studying the structure of the
enzymes that break down purines in the body to achieve a better
understanding of the enzyme defects that can cause gout.
Scientists are studying the effect of crystal deposits on
cartilage cells for clues to gout treatment. They also are looking at the
role of calcium deposits in pseudogout in the hope of developing new
gout treatments. The role genetics and environmental factors play in
hyperuricemia also is being investigated.
Keeping on Top of Your Condition
Keeping in tune with your disease or condition not only makes treatment less intimidating but also increases its chance of success, and has been shown to lower a patients risk of complications. As well, as an informed patient, you are better able to discuss your condition and treatment options with your physician.
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